Page 166 - [Uma_Sekaran]_Research_methods_for_business__a_sk(BookZZ.org)

150 EXPERIMENTAL DESIGNS

hold true in the field setting. To test the causal relationships in the organizational
setting, field experiments are done. These will now be briefly discussed.

THE FIELD EXPERIMENT

A field experiment, as the name implies, is an experiment done in the natural envi-
ronment in which work goes on as usual, but treatments are given to one or more
groups. Thus in the field experiment, even though it may not be possible to con-
trol all the nuisance variables because members cannot be either randomly assigned
to groups, or matched, the treatment can still be manipulated. Control groups could
also be set up in the field experiments. The experimental and control groups in the
field experiment could be made up of the people working at several plants within
a certain radius, or from the different shifts in the same plant, or in some other way.
If there are three different shifts in a production plant, for instance, and the effects
of the piece-rate system are to be studied, one of the shifts can be used as the con-
trol group, and the two other shifts given two different treatments or the same treat-
ment—that is, different piece rates or the same piece rate. Any cause-and-effect
relationship found under these conditions would have wider generalizability to
other similar production settings, even though we may not be sure to what extent
the piece rates alone were the cause of the increase in productivity, because some
of the other confounding variables could not be controlled.

EXTERNAL VALIDITY

What we just discussed can be referred to as an issue of external validity versus
internal validity. External validity refers to the extent of generalizability of the
results of a causal study to other settings, people, or events, and internal valid-
ity refers to the degree of our confidence in the causal effects (i.e., that variable
X causes variable Y). Field experiments have more external validity (i.e., the
results are more generalizable to other similar organizational settings), but less
internal validity (i.e., we cannot be certain of the extent to which variable X
alone causes variable Y). Note that in the lab experiment, the reverse is true. The
internal validity is high but the external validity is rather low. In other words, in
lab experiments we can be sure that variable X causes variable Y because we
have been able to keep the other confounding exogenous variables under con-
trol, but we have so tightly controlled several variables to establish the cause and
effect relationship that we do not know to what extent the results of our study
can be generalized, if at all, to field settings. In other words, since the lab setting
does not reflect the “real world” setting, we do not know to what extent the lab
findings validly represent the realities in the outside world.

TRADE-OFF BETWEEN INTERNAL AND EXTERNAL VALIDITY

There is thus a trade-off between internal validity and external validity. If we
want high internal validity, we should be willing to settle for lower external